help ? very confused

wassup. I just turned 18 today & made this account. 2 years ago I had anxiety and ate lots and lots of junk food. I gained around 25 pounds from this because I totally stopped working out. Ever since then ive been trying to lose but I cant. Im now 6'3 280. People always guess I way around 240 and they always say I dont look that big. I play football & basketball so i always workout with much intensity at the very least an hour a day. I DO NOT EAT OVER 2000 CALORIES. during school I dont even eat breakfast or lunch . The first real meal I have would be around 8pm. I go off to a 3 hour hard practice & come home & eat a light/medium dinner. I never binge.this makes no sense to me. I weigh all the food I eat & its usually 1500-1600 and thats on a heavy day. The weight should be flying off right ? Even after practice I went on the treadmill at a ymca and ran 2 miles in 30 mins & the next day I gained 3 pounds! This was happening at 16-17 years old. I eat less than my lil bro WHO is 5'10 168. He still loses easily. It makes no sense. Its like the harder I go the worst it gets. I now have diarrea, stomach pains, constipation, & gas after eating anything sometimes. My hair stopped growing &people say my face is starting to look older than my actual age . When I was younger I weighed 250 and got down to like 225 fairly easily. Stayed around that weight also until I started having anxiety and eating carelessly 2 years later. In the middle of the football season I started losing weight out of nowhere and I was eating MORE. Couldnt take the chronic hunger any longer. I thought I was going to gain even more. I had burger King after games, countless pb&j's, donuts, honeybuns and etc. I kept losing. Even after a light exercise I lost 3 pounds. I got down to 259. People were saying I was getting skinner. Soon as the season ended I slow gained it back eating less again. Got up to 272 smh. Started doing long cardio like 2500 jump ropes everyday and running a mile. I ate even lesser , 1495 calories . It was exhausting. Got down to 265. The weight started going back up again afterwards again and this left me stuck. If I ate over 2000 calories now the weight got back up to 277. This makes no sense. Im weighing everything !!!!! Ive always been fat from overeating. I acknowledge how i would eat twice as much growing up but now I only eat half as much. I only drink water and I never snack. I dont even have time too! Help !!!